Medical technology has made various attempts to treat internal pathologies such as uterine fibroid tumors, cervical neoplasia and HPV lesions, prostate hyperplasia or cancer, liver cancer, malignant bone and soft tissue sarcoma, and other tissue pathologies. In some instances, rigid needle systems have been devised for purposes of mechanically penetrating tissue and delivering treatment to the tissue. Such systems, however, are difficult to use, particularly when tortuous paths must be followed to reach the target tissue and when the tissue to be treated is resistant to entry of such needles. What is needed is a delivery system for a flexible catheter that can penetrate and destroy tissue masses or tumors of variable size and hardness.